gtest dependency no longer has a 'master' branch

[maudzekod4000]

Hi, good people!
Writing you to inform you that the gtest library no longer has a 'master' branch/tag, so the build of the library with CMake fails.
After changing to 'main' in the CMakeLists.txt of the gtest library I got it working.

[DeepTrial]

I have create a pull request for this tiny change